Misassembly of full-length Disrupted-in-Schizophrenia 1 protein is linked to altered dopamine homeostasis and behavioral deficits.

Disrupted-in-schizophrenia 1 (DISC1) is a mental illness gene first identified in a Scottish pedigree. So far, DISC1-dependent phenotypes in animal models have been confined to expressing mutant DISC1. Here we investigated how pathology of full-length DISC1 protein could be a major mechanism in sporadic mental illness. We demonstrate that a novel transgenic rat model, modestly overexpressing the full-length DISC1 transgene, showed phenotypes consistent with a significant role of DISC1 misassembly in mental illness. The tgDISC1 rat displayed mainly perinuclear DISC1 aggregates in neurons. Furthermore, the tgDISC1 rat showed a robust signature of behavioral phenotypes that includes amphetamine supersensitivity, hyperexploratory behavior and rotarod deficits, all pointing to changes in dopamine (DA) neurotransmission. To understand the etiology of the behavioral deficits, we undertook a series of molecular studies in the dorsal striatum of tgDISC1 rats. We observed an 80% increase in high-affinity DA D2 receptors, an increased translocation of the dopamine transporter to the plasma membrane and a corresponding increase in DA inflow as observed by cyclic voltammetry. A reciprocal relationship between DISC1 protein assembly and DA homeostasis was corroborated by in vitro studies. Elevated cytosolic dopamine caused an increase in DISC1 multimerization, insolubility and complexing with the dopamine transporter, suggesting a physiological mechanism linking DISC1 assembly and dopamine homeostasis. DISC1 protein pathology and its interaction with dopamine homeostasis is a novel cellular mechanism that is relevant for behavioral control and may have a role in mental illness.

Amelioration of relapsing polychondritis in a child treated with oral collagen.

Relapsing polychondritis (RP) is a disease characterized by inflammation and the destruction of cartilage. The detection of antibodies to native type II collagen (CII) in the sera of some patients with relapsing polychondritis suggests that autoimmunity to this cartilage specific protein plays a role in the pathogenesis of the disease. RP is so rare that controlled therapeutic trials have not been carried out. We describe herein a child with RP who had amelioration of symptoms and a deviation in the cellular immune response to CII after being treated with daily oral CII as a toleragen.

Lack of efficacy of oral bovine type II collagen added to existing therapy in rheumatoid arthritis.

OBJECTIVE: To investigate the efficacy of oral type II collagen (CII) in the treatment of rheumatoid arthritis (RA), when added to existing therapy. METHODS: Patients with active RA (n = 190) were randomized into a 6-month, double-blind, placebo-controlled trial. Patients continued to take their current arthritis medications. Patients received either placebo or bovine CII, 0.1 mg/day for 1 month, then 0.5 mg/day for 5 months. RESULTS: There were no significant differences between the baseline characteristics of either group. The primary response parameter was the American College of Rheumatology (ACR) preliminary definition of improvement in RA (ACR 20). There was no statistically significant difference in the ACR 20 after 6 months (20.0% of placebo patients; 16.84% of bovine CII patients). There were significant differences in several clinical variables after treatment, all favoring the placebo group. CONCLUSION: Oral solubilized bovine CII, added to existing therapy, did not improve disease activity in patients with RA.

Pseudothrombophlebitis in neuropathic arthropathy of the shoulder.

The syndrome of pseudothrombophlebitis is a well-known complication of popliteal cysts. We report the case of a patient with a neuropathic arthropathy of the shoulder in whom pseudothrombophlebitis of the upper extremity subsequently developed. To our knowledge, this is the first such case that has been reported.

Aortic mural thrombus presenting as pseudovasculitis.

Three months after splenic infarct, a 50-year-old woman underwent arteriography for persistent low-grade fever and abdominal complaints. After 5 months of corticosteroid therapy for "polyarteritis nodosa," another arteriogram confirmed embolic disease; transesophageal echocardiography (TEE) showed a pedunculated mobile thrombus in the aortic arch. We suggest this represents "pseudovasculitis" from an aortic thrombus.

The amino-terminal 29- and 72-Kd fragments of fibronectin mediate selective monocyte recruitment.

Proteolytic fragments of fibronectin (Fn) can possess properties not inherent to intact Fn. Previously, only mixtures of low molecular weight Fn fragments, and the 120-Kd fibroblastic cell-binding segment, but not intact Fn, were shown to be selectively chemotactic for human monocytes (MOs). In order to determine if other structural domains of Fn were responsible, we tested six Fn fragments. The amino-terminal 72-Kd fragment at 1.5 microns was about 75% as potent as zymosan-activated serum (ZAS). Its amino-terminal 29-Kd degradation product at 1.0 micron was about one third as potent as ZAS. Checkerboard analysis confirmed chemotaxis. Complexing gelatin to 72-Kd fragments reduced MO chemotaxis by 28% to 30%. Reducing disulfide bonds in 29- and 72-Kd segments had no effect. A synthetic peptide containing the thrombin cleavage site between the 29- and 50-Kd segments of the 72-Kd fragment was chemotactic. The 50-, 190/170-, 35-, and 160/150/120-Kd fragments, and intact Fn were not chemotactic for MOs. The data suggest that the 72-Kd fragment and its 29-Kd subfragment are additional Fn fragments that mediate selective MO chemotaxis. We speculate that proteinases present at inflammatory sites can liberate such fragments that selectively recruit MOs.

Institution-wide program for impaired residents at a major teaching hospital.

An institution-wide program for residents impaired by alcohol, other drugs, or emotional problems was established in 1983 at the Medical College of Wisconsin Affiliated Hospitals. The goal of the program was to help impaired house staff members to continue their training in a nonpunitive environment. An approach to reviewing allegations of impairment and a legal agreement between the hospital and the recovering resident were implemented. Because no residents were reported for impairment during its first two years, the program's emphasis was shifted from an investigative to an educational, assistive role. Major problems in carrying out the program have been the program's lack of authority to ensure cooperation by program directors and by impaired residents; a widespread unfamiliarity with intervention procedures despite efforts to inform residents, their spouses, faculty members, and administrators about the program; and misconceptions that the program is punitive. Further impediments are lack of a budget to provide educational activities, inadequate socializing between the faculty and the house staff that would enable faculty members to recognize early signs of impairment; and inadequate health insurance coverage for long-term treatment.

Anterior pituitary involvement in Wegener's granulomatosis.

Wegener's granulomatosis rarely involves the pituitary, and is limited to the posterior gland. A young woman developed sinusitis, otitis media, asymptomatic pulmonary density, blindness, and anterior pituitary hormone deficiency over 7 years. Mucosal biopsies showed only chronic necrotizing inflammation without vasculitis. Since her clinical course suggested an atypical presentation of Wegener's granulomatosis, cyclophosphamide was finally added to corticosteroid therapy. All symptoms but monocular blindness and hypopituitarism remitted.

Rheumatic manifestations of diseases associated with substance abuse.

Rheumatic manifestations of substance abuse are uncommon but recognized complications. Repeated injections of drugs and adulterants represent repeated antigenic challenge. The population at greatest risk is that of young males, although females with eating disorders are more apt to develop myopathy, clubbing, or periostitis. Alcohol, the most common substance abused, is associated more often with myopathy. In IV drug abusers, hepatitis B viral infection, bacterial endocarditis, primary skeletal infections, and venous complications are most common in that order. However, the spectrum may evolve as the pattern of substance abuse changes. First, the frequency of cocaine dependence is rapidly approaching that of alcohol. Two regular cocaine users are reported as having Raynaud's phenomenon and abnormal serologies. Second, synthesis of lookalike drugs may produce new associations, such as parkinsonism after IV N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Third, the increased use of ipecac and purgatives in eating disorders is an important consideration in young women with otherwise unexplained myopathy or arthritis. Finally, patients with AIDS are presenting with autoimmune phenomena or a spectrum of unusual infections that change as the epidemic evolves. Increased recognition of these symptom complexes may lead to earlier, more accurate diagnoses and avoidance of unnecessary diagnostic evaluations and delays in treatment.

Septic spondylodiscitis in ankylosing spondylitis.

A patient with ankylosing spondylitis (AS) for 10 years suddenly developed localized midback pain after minimal activity. Although he sought immediate medical assistance, recognition of a septic spondylodiscitis was delayed 3 weeks. One day after admission, he developed fever and admitted to intravenous drug use. Staphylococcus aureus empyema and spondylodiscitis were subsequently diagnosed. Clinical differentiation of aseptic from septic spondylodiscitis cannot be ignored in patients with AS.

Role of leukocytes in ocular inflammation of tyrosinemia II.

In the animal model of tyrosinemia II only corneas from tyrosine(tyr)-fed rats produce chemoattractants in organ culture. To study the role of neutrophils (PMNs) in production of these chemoattractants, leukocytes (WBCs) were depleted using i.p. cyclophosphamide (CP). Saline (SAL)-treated rats maintained 18,375 +/- 894 WBC/mm3 (mean +/- SEM) with 4168 +/- 424 PMNs. Rats receiving CP (150 mg/kg day 0, 75 mg/kg day 4) has 1565 +/- 170 WBC (565 +/- 129 PMN) on day 3, and 398 +/- 68 WBC (19 +/- 5 PMN) on day 8. Rats ate a low-protein +/- 5% tyr diet on days 4-8. Only SAL-treated tyr-fed rats developed plaque-like gray epithelial lesions; histopathology showed corneal epithelial necrosis, stromal edema, and epithelial and stromal PMN infiltration. Control and CP-treated tyr-fed rat corneas showed no inflammation. On day 8 corneas were cultured in RPMI 1640 + 5% heat-inactivated fetal bovine serum. After 3 days, supernatants were assayed for chemotactic activity (leading front method); data were expressed as the percentage of peritoneal PMN migration relative to 5% zymosan-activated rat serum. The mean total migration toward 75% supernatant from SAL-treated, tyr-fed rat corneas was 79%, whereas migration toward corneal supernatants from controls and CP-treated tyr-fed rats ranged from 42-48%. Corneal extracts were assayed for proteolytic activity. WBC depletion prevented the increase in cathepsin B- and D-like activities present in tyr-fed corneas, suggesting that PMNs were a major source of these enzymes. The data suggest that WBC depletion reduces both corneal inflammation in vivo and the production of chemotactic activity by tyr-fed corneas in culture.

The immune system in experimental Pseudomonas keratitis. Model and early effects.

A model to study the immune system in Pseudomonas keratitis was developed using defined flora rats (WAG/RijMCW) that have not been exposed to Pseudomonas aeruginosa. One group of rats was made immunocompetent towards P. aeruginosa by intraperitoneal injection of phenol-killed P. aeruginosa while a second group remained naive to this organism. Corneas of both groups were scratched centrally with a 21-g needle, before inoculation with 2 X 10(8) P. aeruginosa organisms. Corneas of control animals were either only scratched or only inoculated with the bacterium. At 18 hr, the naive animals were killed. In naive rat corneas, light and electron microscopy showed bacteria throughout the cornea, polymorphonuclear leukocytes (PMNs) distributed from the limbus towards the center, and little stromal degradation. In contrast, massive corneal degradation was observed in the immunocompetent rats; PMNs were present, but no bacteria were observed free in the stroma. The total acid protease content was higher in the immunocompetent than in the naive rat corneas, a possible reason for the observed difference in corneal degradation. This difference was not due to increased numbers of PMNs since nearly equal numbers of PMNs were counted after enzymatic disaggregation of both types of corneas. Glycogen-induced peritoneal PMNs from both types of rats migrated equally well towards P. aeruginosa culture media and media of corneas incubated with this bacterium. The authors conclude that immune recognition is (1) involved in the corneal host response to P. aeruginosa and (2) required for efficient phagocytosis by PMNs but not their recruitment.

Corneal organ cultures in tyrosinemia release chemotactic factors.

Corneal inflammation with subsequent scarring and blindness occurs in the inherited human metabolic disease tyrosinemia type II, yet putative inflammatory mediators in this disorder and in the avascular cornea in general are poorly defined. In a Tyr-fed rat model of tyrosinemia type II, intracellular crystals, presumably Tyr, are hypothesized to be responsible for the increased lysosomal activity observed in corneal epithelial lesions. Because polymorphonuclear leukocytes (PMNs) are seen only at the site of these lesions, we used this model to study humoral mediators released from Tyr-fed rat corneal organ cultures. Only Tyr-fed rats developed stromal edema and linear granular opacities in gray edematous corneal epithelium, compatible with a noninfectious keratitis. Electron micrographs confirmed epithelial edema and showed focal epithelial necrosis with PMN invasion of the stroma. Only Tyr-fed rat corneal culture supernatants contained chemotactic activity that was heat labile and moderately trypsin sensitive. Four peaks with varying amounts of chemotactic activity were found on Sephadex G-75 chromatography. Although the identity of these peaks of activity has not yet been established, we suggest that they may be responsible for the PMN infiltration observed in this model of corneal inflammation.

Chlorpromazine inhibits neutrophil chemotaxis beyond the chemotactic receptor-ligand interaction.

Phenothiazines depress Ca++-dependent neutrophil functions, perhaps by binding to calmodulin or perturbing membrane structure through hydrophobic interactions. We examined effects of chlorpromazine (CPZ) on the human polymorphonuclear neutrophil (PMN) chemotactic-oligopeptide receptor and PMN membrane fluidity. CPZ had a reversible, biphasic effect on PMN motility in the Boyden chamber (slight depression at 5 microM, enhancement at 10 microM, and dose-dependent inhibition at higher concentrations). Order of potency for inhibition of motility (trifluoperazine greater than CPZ greater than promethazine) was identical to that for both inhibition of superoxide (O-2) release and binding to calmodulin. CPZ nonspecifically altered the binding affinity of chemotactic fMet-Leu-[3H]Phe. As assessed with two spin-probes, PMN membrane fluidity was unaltered at CPZ concentrations that depressed PMN receptor-mediated chemotaxis and O-2 release. The data suggest that CPZ nonspecifically alters receptor affinity and depresses chemotaxis and O-2 release independently, without altering bulk membrane fluidity. We speculate that unidentified "post-receptor changes" at a common translocation step for functions tested account for the observed inhibition.

Amphotericin B alters the affinity and functional activity of the oligopeptide chemotactic factor receptor on human polymorphonuclear leukocytes.

Leukocyte chemotaxis is initiated by the binding of chemotactic factors to specific, high-affinity receptors. Amphotericin B, a polyene antibiotic that binds to membrane cholesterol, inhibits human neutrophil (PMN) chemotaxis. We examined the effects of this drug on PMN functions mediated by the oligopeptide chemotactic factor receptor. The antibiotic irreversibly inhibited chemotaxis and depressed the binding of the radiolabeled chemoattractant, fMet-Leu-[3H]Phe, to its receptor without affecting the receptor's specificity. The drug lowered the binding affinity of the receptor by up to fivefold and slightly increased its number. Doses of amphotericin B that depressed receptor affinity and inhibited chemotaxis did not diminish lysosomal enzyme secretion or superoxide anion production. Nystatin, a less potent polyene antibiotic, also diminished chemotactic factor binding, but to a lesser degree than amphotericin B did. A chemically unrelated antifungal agent had no effect on either binding or chemotaxis. Thus, pharmacologic manipulation can alter the affinity of the chemotactic factor receptor on human PMN; this alteration is associated with a change in receptor function. The data suggest that receptor affinity regulates or at least reflects its functional state, and that the transduction mechanisms for various biologic responses mediated by the chemoattractant receptor are heterogeneous. By pharmacologic alterations of receptor affinity, one may be able to modulate specific biologic responses elicited by chemoattractant receptor-ligand interactions.